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May 2015

At the beginning, I started playing as hobbyists with technologies like Zigbee and Z-wave, adding Bluetooth Low Energy to the equation shortly after.

Very quickly, I understood of all challenges and shortcomings, problems related to interoperability between vendors and types of devices ..

Let me step back to the beginning, several years ago, in my first project, I planned on integrating telephony with Home Automation. Imagine being able to call your small Asterisk PBX and using DTMF (tones) control your door lock, or perhaps water your garden. All that just by calling your home and sending some digits from your DTMF keypad. I have decided to use Zigbee as communication protocol between a telephony device (home automation controller) and all our end points. You may ask, why Zigbee? Well, I could get all necessary software from Ti without spending a fortune, so, why not. In a couple of evenings, we designed tiny module for my IP04 and wrote a driver to control it using SPI, just to make it compatible with standard telephony modules used in IP04. For Zigbee chip, I decided on CC2530 by Ti. Together with a friend, we created a Zigbee controller to parse and interpret Zigbee messages and to control our end points. All running on a Blackfin based IP04 PBX. Quickly, we understood that this is not the right way, hard coded rules to open my door were working just fine, but this is not what Home Automation is about.

Our first disappointment? Our Zigbee module would not communicate with commercially available Zigbee controllers. Sounds familiar? If you are involved with Zigbee you probably know what I am talking about.

The actual remedy was “simple”, we just had to change the firmware to use Home Automation profile instead of a private profile we defined initially to communicate with our own controller running on the IP04. To get to that point, wasn’t however easy, as early SDK from Ti did not explain it clearly, and we end up spending countless hours sniffing and comparing our modules to commercially available ones.

To be honest, once we figured out that profile definition was causing our pain, we fixed it in a couple of hours. In the meantime, we have learnt that Zigbee is not yet very popular in Home Automation world and if we want to have access to variety of inexpensive devices we need to look at another technology, and this is how we started looking at Z-wave…

See my next blog for description of differences between those two great wireless protocols and pros and cons from our perspective.